code: def test_document_store_class_default():
      MyStore = document_store_class("MyStore")
      store = MyStore()
      assert store.count_documents() == 0
      assert store.filter_documents() == []
      assert store.write_documents([]) is None
      assert store.delete_documents([]) is None
      assert store.to_dict() == {
          "type": "haystack.testing.factory.MyStore",
          "init_parameters": {},
      }
  
file_path: haystack/test/testing/test_factory.py
imports: import pytest
  from haystack.dataclasses import Document
  from haystack.testing.factory import document_store_class, component_class
  from haystack.core.component import component
label_desc: Use image node_id 1 for calling a global function with example usage: test_document_store_class_default() without return types